The present invention relates to cleansing compositions comprising one or more surfactants selected from the group consisting of: i) anionic surfactants, ii) amphoteric surfactants, iii) nonionic surfactants, iv) cationic surfactants and v) mixtures thereof, where the dynamic viscosity of the compositions at 25xc2x0 C. is at least about 100,000 centipoise and where the cleansing composition results in no or minimal eye sting.
The instant cleansing compositions are preferably used in releaseable combination with a disposable substrate as a personal cleansing product.
Personal care products, particularly cleansing and conditioning products, have traditionally been marketed in a variety of forms such as bar soaps, creams, lotions, and gels. Typically, these products must satisfy a number of criteria to be acceptable to consumers. These criteria include cleansing effectiveness, skin feel, mildness to skin, hair, and ocular mucosae, and lather volume. Ideal personal cleansers should gently cleanse the skin or hair, cause little or no irritation, and should not leave the skin or hair overly dry after frequent use. Further, cleansing compositions, particularly shampoos, designed for use with children should exhibit mildness to the ocular mucosae, and no or minimal eye sting, should material from the cleansing composition be placed in the eye.
U.S. Pat. No. 5,139,705 (Wittpenn, Jr., et al.) discloses mild non-irritating surfactant compositions which include an anionic surfactant, an amine oxide, a nonionic surfactant having a relatively low melting point and a nonionic surfactant having a high melting point relative to the low melting point nonionic surfactant. The compositions of Wittpenn, Jr., et al. contain approximately 90% water. The viscosity requirements of the products of the instant invention would not be met by Wittpenn""s compositions.
It is highly desirable to deliver cleansing and conditioning benefits from a disposable substrate. Disposable products are convenient because they obviate the need to carry or store cumbersome bottles, bars, jars, tubes, and other forms of clutter associated with cleansing products and other products capable of providing therapeutic or aesthetic benefits. Disposable products are also a more sanitary alternative to the use of a sponge, washcloth, or other cleansing implement intended for extensive reuse, because such implements can develop bacterial growth, unpleasant odors, and other undesirable characteristics related to repeated use.
There is also a need for personal care articles, such as disposable washcloths, which can be easily used by young children. Such child-friendly personal care products must be easy to handle and the method of utilizing them must be easily understood. In addition to mildness to the ocular mucosae, there should be no or minimal eye sting, should material from the cleansing composition contact the eye while a child is using the article. Therefore, the invention encompasses disposable cleansing articles wherein the cleansing composition produces no or minimal eye sting when introduced into the eye.
Disposable substrates containing mild cleansing compositions producing no or minimal eye sting, would also facilitate such tasks as make-up removal (particularly eye make-up) and cleaning of animals, such as pets.
While a variety of cleansing compositions associated with substrates are known in the art, they are not appropriate for use where substantial amounts of cleansing composition can be deposited into the eye. The present invention overcomes these problems by providing a cleansing composition which generates no or minimal eye sting.
The present invention relates to cleansing compositions in paste form comprising one or more surfactants selected from the group consisting of: i) anionic surfactants, ii) amphoteric surfactants, iii) nonionic surfactants, iv) cationic surfactants, and v) mixtures thereof, where the viscosity of the compositions at 25xc2x0 C. is at least about 100,000 centipoise and where the cleansing composition results in no or minimal eye sting.
One embodiment of the cleansing composition has a first dynamic viscosity at 25xc2x0 C. and a second dynamic viscosity over a temperature range of 60xc2x0 C. to 125xc2x0 C., said first and second dynamic viscosities having a ratio of said first dynamic viscosity to said second dynamic viscosity greater than or equal to about 1.1.
In addition embodiments of the cleansing composition have a first flow viscosity at 25xc2x0 C. and a second dynamic viscosity over a temperature range of 60xc2x0 C. to 125xc2x0 C., said first and second flow viscosities having a ratio of said first flow viscosity to said second flow viscosity greater than or equal to about 1.1.
Compositions exhibiting these preferred ratios of viscosities are extremely viscous at room temperature (25xc2x0 C.) but become liquid at relatively low temperatures, allowing for ease in processing while contributing to stability on the substrate, i.e., the instant cleansing compositions tend to remain on the substrate due to their viscosity at room temperature. Cleansing compositions with the above characteristics are considered xe2x80x9chot meltxe2x80x9d surfactant compositions.